An engineer accused of raping and murdering his girlfriend threw water in her face and turned the lights off when she was showering during a two-year campaign of abuse, a court heard.
Stephen Sexton, 39, also broke Joanna Derkacz's phone and laptop because he was 'jealous' and didn't like her going out, jurors were told.
A tearful Ms Derkacz, 37, a recruitment consultant, was recorded on a police worn body camera telling officers he was 'aggressive' and would 'flip' just three weeks before she was killed.
But she said he 'knew what he was doing' as his father was a police officer.
She was found dead in December 2023 at the flat she shared with Sexton in Waterlooville, Hampshire, having been raped and strangled.
The father-of-one proceeded to contact two prostitutes immediately afterwards, and took Joanna's car to visit one after sending a message saying 'I'll be there in 20 minutes ok baby,' jurors were told.
Sexton, of Totton, Southampton, denies murder, rape and coercive or controlling behaviour at Winchester Crown Court.
Sexton allegedly strangled Joanna Derkacz at their flat after their relationship broke down
Stephen Sexton, 39, denied murdering Joanna Derkacz, 37, after their relationship broke down
Miss Derkacz was found dead at their home in Waterlooville, Hants, on December 28, 2023
The court heard that three weeks before she was killed, police carried out a welfare check on Ms Derkacz at her flat after Sexton reported her missing when she came home late following a night out with friends.
Police initially assessed the risk to Ms Derkacz as 'medium' then before it was reviewed and reassessed as 'high risk'.
In the footage played to jurors she said Sexton had been 'very controlling' and 'very narcissistic' to her and he had 'flipped' because she had been late after a night out.
Sexton was not at the address when the police arrived, and they spoke to Ms Derkacz about what had happened when she was supposedly gone missing.
Ms Derkacz showed them the laptop that he had broken that morning by 'stamping on it' when they got into an argument.
She said: 'He is very controlling. He is very narcissistic. He doesn't like me going out anywhere. I don't know if he took something because he has got that thing where he flips.
'He started accusing me like, 'You slut.' But I was staying with some friends.
'Obviously, he was aggressive towards me. Obviously, he does have some mental problems. I think his ex-partner reported him before.
'I get it, he has got the anger issue, and I thought I could control him. This night I couldn't stop him.
'I do want to protect him. He is my partner but I can't keep doing the same shit.
'I started watching TV. He took the controller from me. I went to use my laptop and he took my laptop upstairs and started jumping on it.
'I went through this so many times and I am trying to not tell anyone what is going on in my life because I don't want people to see him in that light.'
Joanna Derkacz told police three weeks before she was killed that Sexton would 'flip'
Ms Derkacz said that in the morning, she came back from the night out, he took 'massive glasses of water' and splashed them over her face.
Ms Derkacz said: 'I said to him, 'Do you realise what you have done'. I have had enough of him saying fucking sorry all the time.
'He is always threatening me that he is going to take the dogs. He is so fucking spiteful that I can't.
'The way that he is manipulating me. The way that he is horrible.
'I took a shower the other day, and he kept switching the lights out, so I had a shower in the dark. He is trying to make a point that he is not happy.'
Ms Derkacz said that she had been dating Sexton for three years and that she faced abusive behaviour for two and a half years.
She said: 'The reason I am still with him is he does have a good side. I don't know if he is bipolar or something but he does flip.'
Ms Derkacz said that Sexton's dad was a police officer 'so he knows what he is doing'.
She said that she told the police about the abuse because Sexton had called them over and it was 'the perfect opportunity' to tell them.
When Police Constable Abigail Gilbert asked Miss Derkacz if she felt isolated from her friends, she said: 'Yes. When I go out he makes me feel like I have done something wrong or he just messages me all the time.
'My sister doesn't talk to him anymore because he had a flip.
'He is so jealous that he says I am a slut. I am cheating on him but this is just a reflection on him.
'He already started to destroy every single friendship that I have because he is toxic.'
PC Gilbert asked if she wanted to give a statement about the broken laptop and if she wanted to take the matter any further, but she declined.
Ms Derkacz said that, as they had split up, she was going to try to sort the living situation with the estate agent as they had a joint lease, but he could go and stay with his parents.
She agreed that she would contact the police if she needed any more assistance but she was a very 'private person'.
PC Gilbert added: 'My risk assessment at the time was medium. It was later reviewed and it was assessed as high level.'
Prosecutors said Ms Derkacz made a 'fatal mistake in underestimating him.'
The court heard there were 'so many red flags' but neither she nor the officers realised how far Sexton might go 'when he realised she was slipping from his grasp'.
The trial continues.